Fan construction



Dec. 13, 1938. G. H. KOCH 2,140,017

FAN CONSTRUCTION Filed Ju1y'415, 1938 WITNEssl-:s: FIG. 2 INVENTQRGus-rnv H. Koen.

ATTORN Patented Dec. 13, 1938 UNITED STATES FAN CONSTRUCTION Gustav H.noch, springfield, Mass., assigner 'to Westinghouse Electric '&Manufacturing Company, East Pittsburgh, Pa., a corporation ofPennsylvania Application July 15, 193s, serial. No. 219,297 u claims.

My invention relates to fans and has for an object to provide improvedapparatus of this kind.

A further object of the invention is to provide 5 an improved fanconstruction that may be readily balanced without affecting theappearance of the fan.

Heretofore, it has been the practice to statically balance the fanblades of domestic or other fans lo in which appearance is of majorimportance by either of two methods. In accordance with the firstmethod, displacement of one or more of the blades so as to 4change theangular relation between adjacent blades in the plane of rotation is l5effected for redistributing the weight about the axis. The second methodincludes removing weight from one or more of the blades by grinding.

The iirst method has been more generally used as it covers a greaterrange of unbalance without disturbing the appearance of symmetry. Theindividual blade mass is displaced by manually bending the supportingarm of the blade ina region near the hub. It will be apparent that inadjusting the blade in this manner, the pitch angle of this region ofthe blade structure would be disturbed. After obtaining the properstatic balance, usually by several applications of the bending tool andseveral checks on the balance ways, it is therefore, necessary to checkthe blade for pitch and position in the plane of rotation. Ifcorrections are necessary, the static balance will. probably bedisturbed to a sufficient extent to The second method of balancing canonly be applied where the amount of correction is limited, since theblades of fans of the type set forth are quite thin and do not permitremoval of much material at the outer ends thereof. Furthermore, it isnecessary to follow the grinding operation with a polishing operation inorder to removethe grinder marks. Considerable experi- I 5o ence isnecessary for the operator to decide how much correction should be leftfor the polishing operation. It will be apparent that, as in the i'lrstl method, quantitative methods to determine unbalance are notapplicable.

v In practicing my invention, I provide an improvedfan constructionwhich may betested by known methods wherein the unbalance isquantitatively determined, after whichbalance weights may be readilyapplied to the fan without de tractng from the appearance thereof. 5

It is, therefore, a prime object of my invention to provide an improvedfan construction to which balancing weights may be applied withoutdetracting from the appearance of the fan subsequent to testing the fanfor unbalance. 10

The foregoing and other objects are effected by my invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawing forming a part of this application, inwhich: 15

'Figs l and 2 are rear and side views, respectively, of a fanconstructed and arranged in accordance with my invention; and

Fig. 3 is a sectional view taken along the line III-III of Fig. 2. f

Reference will now be had to the drawing wherein I have shown myinvention applied to a fan of the type commonly employed for thecirculation of air in residences, commercial establishments or the like.The fan structure includes a 25 hub l0 having arms II extending radiallytherefrom for the support of blades I2, that are secured in any suitablemanner to the arms Il, preferablyby rivets I3. Rotation of the hub I0 iseifected by a shaft I4 secured to the hub and 30 driven by a motor (notshown).

In accordance with my invention, the arms I I are provided with recessesor openings I5 formed in any suitable manner, preferably by piercing.The openings I5 are covered by the blades I2 at 35 the front end thereofso that they are not visible from the front side of the fan and,therefore, do not detract from the appearance of the fan as viewed fromthe front thereof. The openings I5 are formed to receive discs I6 ofvarious 40 Weights and vemployed to balance the fan. Thediscs I6 may besecured within the openings I5 in any suitable manner. As shown, thediscs I6 are dished and expanded within the walls of the openings I5. Itwill be apparent that the balanc- 45 ing discsY I6 are not in view fromthe front ofthe fan and are not discernible from the rear thereof sothat the appearance of symmetry is not disturbed by their use.

After the blades I2 and hub I0 are assembled, 50 they may be tested'forbalance in any well understood manner in which the degree of unbalanceis quantitatively determined and theunbalanced region is located. DiscsI6 of the proper-weight as determined by the test are expanded in theproper opening i 5 for balancing the fan. 'I'he discs I6 may be ofdifferent thicknesses and formed of materials of different specificgravity for obtaining a relatively large number of balancing discs ofdifferent weight suitable for insertion in the openings l5. Furthermore,the openings l5 in each arm may be of dierent size, as shown, so thatdiscs of different diameters may be employed whereby the range of Weightvalues of the discs is further increased.

From the foregoing, it will be apparent that I have provided an improvedfan construction that may be balanced without aifecting the appearanceof symmetry of .the fanl and wherein balance weights are employed, whichare not materially discernible.

While I have shown two openings of different size for receiving thebalancing members, it will be understoodA that one ormore openings maybe provided without departing from the spirit of the invention.

While I have shown my invention in but one form, it will be obvious tothose skilled in the -art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof, and I desire, therefore, that only such limitations shall beplaced thereupon as are imposed by the prior art or as are specificallyset forth in the appended cessible Afrom the other side of the arms, andbalancing members insertable into said openings for balancing the bladeand hub assembly.

2. In a fan construction, the combination of a hub having a pluralityvof arms extending radially therefrom, each of said arms having a recessformed therein and accessible from the rear side of the arms, aplurality of fan blades secured to the front side of the respective armsand balancing discs insertable in said recesses for balancing the bladeand hub assembly.

3. In a fan construction, the combination of a rotatable hub having aplurality of arms extending radially therefrom, a plurality of fanblades secured to the one side of the respective arms, each oi said armshaving an opening extending therethrough and-covered by the bladesecured thereto, and balancing weights insertable in the openings forbalancing the blade and hub assembly.

4, In a fan construction, the combination of a hub having a plurality ofarms extending radially therefrom, each of said arms having radiallyspaced openings formed therein, a plurality of fan blades secured to thefront side of the respective arms and covering the openings therein, anddiscs for balancing the fan construction insertable in said openings.

5. In a fan construction, the combination of a' hub having `radiallyprojecting portions, a ian blade Xedly secured to Aone side of eachpro,- jecting portion, said projecting portions having openings providedtherein and said openings being covered bythe fan blades, and Weightmembers insertable into said openings for balancing the fan blade andhub, assembly.

- GUSTAV-H. KOCH.

